Daisychaining through Thunderbolt RAID to Blackmagic Ultrastudio 4K?

[Thomas Koba]

When unpacking and connecting my Blackmagic Ultrastudio 4K to my new Mac Pro, I discovered unfortunantly, that it's waaayy to loud for such a small unit. So I need to put it in my RAID server location away from the studio. I have a 10 meter optical Thunderbolt cable running to my Areca RAID unit. Would it be okay to daisychain my Ultrastudio to the Areca? I have no idea or sense of how many bits run through such an operation. What you think? Do I need to buy another 10 meter Thunderbolt cable just for my Ultrastudio 4K?

 

[Blair S. Paulsen]

I suppose you could try the daisy chain and see how it goes. Sadly, I think another $300 optical TB2 cable is going to be needed to avoid choking the RAID or dropping frames. Even if the single pipe could theoretically pass enough data, which it probably could when the RAID isn't too busy, I'd expect lots of problems.

Cheers - #19

 

[Jeff Kilgroe]

I'm also in agreement about the secondary optical cable. But you can try it with what you have. The first device on the chain has bandwidth priority and if either device are the older Thunderbolt 1 models, then it will drop the chain into TB1 operational mode, meaning that the first device on the chain will take the primary 10Gbps channel, the second device will take the next channel. That second channel doesn't have a full 10Gbps because of the lack of a full 20Gbps to the TB port. If they're both Thunderbolt 2 versions, then they share the two 10Gbps channels for an aggregate 20Gbps total. But the same PCIe v2.0 backing limitation still exists, meaning 16.7 Gbps maximum to the TB port and don't forget the 10-bit-per-byte translation overhead.

Not sure which one would be the better to have on the chain first. I can see dropped frames or other issues happening due to either one falling short on bandwidth. Placing the RAID on the chain second might be better. However when the UltraStudio is in use, the RAID speeds could drop to half or less of what they should be.

Be careful connecting devices to your new Mac Pro's TB ports in terms of what is placed onto which ports. There are 6 ports, but there are only 3 hosts. The bottom two ports share a host. The the upper two on the left share a host, and the upper two on the right share another.

 

[Thomas Koba]

Ok, thanks. Just initialising my RAID now, so I will check later.

By the way, just curious. Is there any loss in bandwith/quality while using these 10 meters optical Thunderbolt cables?

 

[Clark Dunbar]

here's the link to the Corning Optical Cables

http://www.corning.com/opcomm/OpticalCablesbyCorning/